In an oven of the aforesaid type, there is the known problem that on operating the heat generator (resistance element or burner) the transparent, generally glass surface (window) of the usual closure door heats up and attains high temperature.
In particular and by way of example, if the oven temperature reaches 250.degree. C., the outer surface of the door window reaches temperatures close to 90.degree. C.
This can obviously cause problems if the user inadvertently touches said surface.
Various solutions have been proposed to overcome this problem, one of which, forming the subject of a prior proposal of the present applicant, relates to a door in which a window is provided comprising, within the body of the door, two surfaces of transparent material, preferably glass, said surfaces being positioned parallel to each other and at a short distance apart. This door is characterized in that a further wall of a material that is not transparent to heat, e.g., to radiant energy is inserted between said two surfaces, and is spaced apart at least from that surface more outwards of the oven cooking chamber, said wall comprising at least one aperture which enables the user to see into the interior of the oven. Preferably, air circulation is provided within the interspaces present between each surface and said wall.
Although this solution solves the aforesaid problems relative to excessive heating of the outer surface of the door window, it does not enable this surface to be kept at a temperature very close to the temperature of the environment in which the oven is located. In addition, the aperture provided in the wall between the inner and outer surfaces of said window does not always allow good visibility of the oven interior.
Again, if this aperture is constructed by providing a number of perforations in said wall (to form a sort of grating), the user can view the interior of the oven only from a predetermined position, and this can prove uncomfortable.